Aboard modern aircraft, when an electrical device is installed, be it for example a computer or in general any electrical consumer, a circuit breaker is used to protect its electrical circuit against overloads or short-circuits.
The circuit breakers, which may exceed several hundred in number, are arranged in matrix fashion, in rows and columns, on distribution panels 10, as illustrated in FIG. 1, the said panels being installed mainly in the flight deck or the holds.
When an aircraft is in service or if its definition at an advanced stage of its manufacture is altered and additional electrical devices have to be installed, it is necessary to add circuit breakers.
The panels are therefore designed, when the aircraft is put into service, to be able to receive additional circuit breakers. The said panels thus comprise free sites for receiving these circuit breakers when electrical devices are added.
Furthermore, having regard to the large number of circuit breakers and the non-accessibility of certain distribution panels in the course of the flight of the aircraft, such as those situated in the holds of the aircraft, a monitoring system is used to permanently check the state of each circuit breaker. Upon a change of state of a circuit breaker, the monitoring system informs the other systems and the pilot of the status, and in particular of the changes of states, of the circuit breakers, which act so as to take into account the consequences of this change of state.
To carry out this state monitoring of the circuit breakers, a cabling of the circuit breakers according to rows and columns is commonly used in such a way that reading an item of information according to a row and a column gives the state of the circuit breaker which is positioned at the intersection of the said row and the said column.
When a modification has to be performed, for example, the addition or the removal of an electrical device, a prevailing solution consists in adding or removing the associated circuit breaker or circuit breakers on the distribution panel. Each modification also entails a modification of the cables for monitoring the state of the circuit breakers. Thus, when a circuit breaker is added or removed, the associated monitoring cables are likewise added, removed or replaced. These various modifications give rise to very different cabling between aircraft, which is perpetually being altered and is relatively expensive as regards the time required to install or deinstall the monitoring cables, depending on the presence or otherwise of circuit breakers.